1. Field of the invention
This invention relates to a seal device for generator that are cooled by hydrogen gas.
2. Description of the Prior Art
A large-scale turbine generator hermetically contains hydrogen gas that has the highest heat transfer coefficient among gases to cool the inside of the generator. One of devices to seal hydrogen gas in the generator is disclosed for example by a shaft seal device of Japanese Patent Laid-open No. Hei 5(1993)-146118. This shaft seal device contains two seal rings. One of the seal rings faces hydrogen gas inside the generator and the high-pressure oil supply side. The other seal ring faces the high-pressure oil supply side and the outside of the generator.